With the Global Financial Crisis, the COVID-19 pandemic, and the looming Climate Change, investors and policymakers around the world are bracing for a new global environment with heightened tail risk. Asymmetric exposure to this risk across countries raises the private and social value of arrangements improving insurance. We offer an analytical decomposition of the welfare effects of efficient capital market integration into a "smoothing" and a "level effect". Enhancing risk sharing affects the volatility of consumption, but also brings about equilibrium adjustment in asset and goods prices. This in turn drives relative wealth and consumption, as well as labor and capital allocation, across borders. Using model simulation, we explore quanti...